Current research in isolation and identification of pheromones active in the reproductive behavior of the hamster will be continued and expanded in order to identify compounds in the vaginal secretion of the estrous female that (1) serve as attractants of the male (other than dimethyl disulfide); (2) serve as mounting stimulant for the male; (3) increase plasma testosterone levels in the male; (4) mask or inhibit these various effects. Dose-response relationships for these active compounds will be established using quantitative gas chromatographic and capillary delivery methods. In addition the chemical constituents of the hamster flank gland will be isolated and identified. Isolation techniques used are distillation, reversible absorption on porous resins, and preparative gas chromatograhy using flame ionization, flame photometric, and electron capture detectors. Identification methods to be used in addition to mass spectrometry (separately supported) include submilligram-scale infrared, ultraviolet, and nuclear magnetic resonance spectrometry, as well as chemical transformations.